With 3 chameleons I would say get an automated system if you can afford it.
They are awesome!
If you have to sit there and spray each cage for 5 minutes 3 times a day that equals 45 minutes a day of hand spraying.
I dont mist for longer than 30 seconds twice a day when i do it by hand.
I have upgraded to a PM and it is really worth its weight in gold.